Our long-term goal is to develop a better understanding of persons at risk for alcoholism. Alcohol addiction is a behavioral disorder that has genetic and environmental contributions. Prevalence within families and adoption studies indicate that the risk for alcoholism is one expression of more basic traits that have heritable components. The planned studies are based on the hypothesis that central nervous system processes that integrate emotional behavior are altered in persons at high risk for alcoholism relative to low risk persons. We predict that altered emotion processing will have three markers that should distinguish high-risk individuals. These are: 1) the person's characteristic balance of positive to negative emotions, 2) emotion-related changes in the stress hormone, cortisol, and 3) a measure of emotion-related change in central activation, the startle eyeblink. A random telephone survey of the Oklahoma City area will be used to identify 180 men and women, 18-25 years of age, who are low risk, having a negative family history of alcoholism and social drinking patterns, or high risk, with a positive family history and social drinking patterns. Two related studies are proposed. In Study 1, we will compare the groups using a standard paradigm to examine startle eyeblink magnitude and the emotion modulation of startle that normally occurs to negative and positive emotion-producing stimuli. In Study 2, we will extend that paradigm by examining the emotion modulation of the startle eyeblink together with cortisol responses to a negatively affective challenge. Normal affective response to events depends on interactions among the frontal cortex and limbic areas, while the expression of emotions via motoric and endocrine responses depends on normal regulation by the hypothalamus and brainstem. A finding of consistent changes in affective experience, along with altered peripheral physiological responses, can provide insights into the underlying alterations in emotional behavior in risk for alcoholism.